/*
  This file is part of TALER
  Copyright (C) 2014-2020 Taler Systems SA

  TALER is free software; you can redistribute it and/or modify
  it under the terms of the GNU Lesser General Public License as
  published by the Free Software Foundation; either version 2.1,
  or (at your option) any later version.

  TALER is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with TALER; see the file COPYING.LGPL.  If not,
  see <http://www.gnu.org/licenses/>
*/
/**
 * @file lib/merchant_api_post_orders.c
 * @brief Implementation of the POST /orders
 * @author Christian Grothoff
 * @author Marcello Stanisci
 */
#include "platform.h"
#include <curl/curl.h>
#include <jansson.h>
#include <microhttpd.h> /* just for HTTP status codes */
#include <gnunet/gnunet_util_lib.h>
#include <gnunet/gnunet_curl_lib.h>
#include "taler_merchant_service.h"
#include <taler/taler_json_lib.h>
#include <taler/taler_signatures.h>
#include <taler/taler_curl_lib.h>


/**
 * @brief A POST /orders Handle
 */
struct TALER_MERCHANT_PostOrdersOperation
{

  /**
   * The url for this request.
   */
  char *url;

  /**
   * Handle for the request.
   */
  struct GNUNET_CURL_Job *job;

  /**
   * Function to call with the result.
   */
  TALER_MERCHANT_PostOrdersCallback cb;

  /**
   * Closure for @a cb.
   */
  void *cb_cls;

  /**
   * Reference to the execution context.
   */
  struct GNUNET_CURL_Context *ctx;

  /**
   * Minor context that holds body and headers.
   */
  struct TALER_CURL_PostContext post_ctx;
};


/**
 * Function called when we're done processing the
 * HTTP POST /orders request.
 *
 * @param cls the `struct TALER_MERCHANT_PostOrdersOperation`
 * @param response_code HTTP response code, 0 on error
 * @param json response body, NULL if not JSON
 */
static void
handle_post_order_finished (void *cls,
                            long response_code,
                            const void *response)
{
  struct TALER_MERCHANT_PostOrdersOperation *po = cls;
  const char *order_id = NULL;
  struct TALER_ClaimTokenP token = {0};
  const json_t *json = response;
  struct TALER_MERCHANT_HttpResponse hr = {
    .http_status = (unsigned int) response_code,
    .reply = json
  };
  bool has_token = ((NULL != json_object_get (json,
                                              "token")) &&
                    (false == json_is_null (json_object_get (json,
                                                             "token"))));
  struct GNUNET_JSON_Specification spec[] = {
    GNUNET_JSON_spec_string ("order_id",
                             &order_id),
    (!has_token) ?
      GNUNET_JSON_spec_end () :
      GNUNET_JSON_spec_fixed_auto ("token",
                                   &token),
    GNUNET_JSON_spec_end ()
  };

  po->job = NULL;
  switch (response_code)
  {
  case 0:
    hr.ec = TALER_EC_INVALID_RESPONSE;
    break;
  case MHD_HTTP_OK:
    if (GNUNET_OK !=
        GNUNET_JSON_parse (json,
                           spec,
                           NULL, NULL))
    {
      GNUNET_break_op (0);
      hr.http_status = 0;
      hr.ec = TALER_EC_PROPOSAL_REPLY_MALFORMED;
    }
    break;
  case MHD_HTTP_BAD_REQUEST:
    hr.ec = TALER_JSON_get_error_code (json);
    hr.hint = TALER_JSON_get_error_hint (json);
    /* This should never happen, either us or
       the merchant is buggy (or API version conflict);
       just pass JSON reply to the application */
    break;
  case MHD_HTTP_CONFLICT:
    hr.ec = TALER_JSON_get_error_code (json);
    hr.hint = TALER_JSON_get_error_hint (json);
    break;
  case MHD_HTTP_FORBIDDEN:
    /* Nothing really to verify, merchant says one
       of the signatures is invalid; as we checked them,
       this should never happen, we should pass the JSON
       reply to the application */
    hr.ec = TALER_JSON_get_error_code (json);
    hr.hint = TALER_JSON_get_error_hint (json);
    break;
  case MHD_HTTP_NOT_FOUND:
    /* Nothing really to verify, this should never
       happen, we should pass the JSON reply to the application */
    hr.ec = TALER_JSON_get_error_code (json);
    hr.hint = TALER_JSON_get_error_hint (json);
    break;
  case MHD_HTTP_INTERNAL_SERVER_ERROR:
    /* Server had an internal issue; we should retry,
       but this API leaves this to the application */
    hr.ec = TALER_JSON_get_error_code (json);
    hr.hint = TALER_JSON_get_error_hint (json);
    break;
  case MHD_HTTP_GONE:
    /* The quantity of some product requested was not available. */
    // FIXME: parse the OutOfStockResponse.
    break;
  default:
    /* unexpected response code */
    hr.ec = TALER_JSON_get_error_code (json);
    hr.hint = TALER_JSON_get_error_hint (json);
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Unexpected response code %u/%d\n",
                (unsigned int) response_code,
                (int) hr.ec);
    GNUNET_break_op (0);
    break;
  }
  po->cb (po->cb_cls,
          &hr,
          order_id,
          has_token ? &token : NULL);
  if (MHD_HTTP_OK == response_code)
    GNUNET_JSON_parse_free (spec);
  TALER_MERCHANT_orders_post_cancel (po);
}


/**
 * POST an order to the backend and receives the related proposal.
 *
 * @param ctx execution context
 * @param backend_url URL of the backend
 * @param order basic information about this purchase,
 *        to be extended by the backend
 * @param refund_delay how long can refunds happen for this order; 0 to use
 *             absolute value from contract (or not allow refunds).
 * @param cb the callback to call when a reply
 *        for this request is available
 * @param cb_cls closure for @a proposal_cb
 * @return a handle for this request, NULL on error
 */
struct TALER_MERCHANT_PostOrdersOperation *
TALER_MERCHANT_orders_post (struct GNUNET_CURL_Context *ctx,
                            const char *backend_url,
                            const json_t *order,
                            struct GNUNET_TIME_Relative refund_delay,
                            TALER_MERCHANT_PostOrdersCallback cb,
                            void *cb_cls)
{
  return TALER_MERCHANT_orders_post2 (ctx,
                                      backend_url,
                                      order,
                                      refund_delay,
                                      NULL,
                                      0,
                                      NULL,
                                      0,
                                      NULL,
                                      true,
                                      cb,
                                      cb_cls);
}


/**
 * POST to /orders at the backend to setup an order and obtain
 * the order ID (which may have been set by the front-end).
 *
 * @param ctx execution context
 * @param backend_url URL of the backend
 * @param order basic information about this purchase, to be extended by the backend
 * @param refund_delay how long can refunds happen for this order; 0 to use
 *             absolute value from contract (or not allow refunds).
 * @param payment_target desired payment target identifier (to select merchant bank details)
 * @param inventory_products_length length of the @a inventory_products array
 * @param inventory_products products to add to the order from the inventory
 * @param lock_uuids_length length of the @a uuids array
 * @param uuids array of UUIDs with locks on @a inventory_products
 * @param create_token whether to create a claim token
 * @param cb the callback to call when a reply for this request is available
 * @param cb_cls closure for @a cb
 * @return a handle for this request, NULL on error
 */
struct TALER_MERCHANT_PostOrdersOperation *
TALER_MERCHANT_orders_post2 (
  struct GNUNET_CURL_Context *ctx,
  const char *backend_url,
  const json_t *order,
  struct GNUNET_TIME_Relative refund_delay,
  const char *payment_target,
  unsigned int inventory_products_length,
  const struct TALER_MERCHANT_InventoryProduct inventory_products[],
  unsigned int uuids_length,
  const struct GNUNET_Uuid uuids[],
  bool create_token,
  TALER_MERCHANT_PostOrdersCallback cb,
  void *cb_cls)
{
  struct TALER_MERCHANT_PostOrdersOperation *po;
  json_t *req;
  CURL *eh;
  const char *delay_s;

  delay_s = GNUNET_STRINGS_relative_time_to_string (refund_delay,
                                                    GNUNET_NO);
  po = GNUNET_new (struct TALER_MERCHANT_PostOrdersOperation);
  po->ctx = ctx;
  po->cb = cb;
  po->cb_cls = cb_cls;
  po->url = TALER_url_join (backend_url,
                            "private/orders",
                            NULL);
  req = json_pack ("{s:O}",
                   "order", (json_t *) order);
  GNUNET_assert (NULL != req);
  if (0 != refund_delay.rel_value_us)
  {
    GNUNET_assert (0 ==
                   json_object_set_new (req,
                                        "refund_delay",
                                        GNUNET_JSON_from_time_rel (
                                          refund_delay)));
  }
  if (NULL != payment_target)
  {
    GNUNET_assert (0 ==
                   json_object_set_new (req,
                                        "payment_target",
                                        json_string (payment_target)));
  }
  if (0 != inventory_products_length)
  {
    json_t *ipa = json_array ();

    GNUNET_assert (NULL != ipa);
    for (unsigned int i = 0; i<inventory_products_length; i++)
    {
      json_t *ip;

      ip = json_pack ("{s:s, s:I}",
                      "product_id",
                      inventory_products[i].product_id,
                      "quantity",
                      (json_int_t) inventory_products[i].quantity);
      GNUNET_assert (NULL != ip);
      GNUNET_assert (0 ==
                     json_array_append_new (ipa,
                                            ip));
    }
    GNUNET_assert (0 ==
                   json_object_set_new (req,
                                        "inventory_products",
                                        ipa));
  }
  if (0 != uuids_length)
  {
    json_t *ua = json_array ();

    GNUNET_assert (NULL != ua);
    for (unsigned int i = 0; i<uuids_length; i++)
    {
      json_t *u;

      u = json_pack ("{s:o}",
                     "uuid",
                     GNUNET_JSON_from_data_auto (&uuids[i]));
      GNUNET_assert (NULL != u);
      GNUNET_assert (0 ==
                     json_array_append_new (ua,
                                            u));
    }
    GNUNET_assert (0 ==
                   json_object_set_new (req,
                                        "lock_uuids",
                                        ua));
  }
  if (! create_token)
  {
    GNUNET_assert (0 ==
                   json_object_set_new (req,
                                        "create_token",
                                        json_boolean (create_token)));
  }
  eh = curl_easy_init ();
  GNUNET_assert (NULL != eh);
  if (GNUNET_OK != TALER_curl_easy_post (&po->post_ctx,
                                         eh,
                                         req))
  {
    GNUNET_break (0);
    json_decref (req);
    GNUNET_free (po);
    return NULL;
  }
  json_decref (req);
  GNUNET_assert (CURLE_OK ==
                 curl_easy_setopt (eh,
                                   CURLOPT_URL,
                                   po->url));
  po->job = GNUNET_CURL_job_add2 (ctx,
                                  eh,
                                  po->post_ctx.headers,
                                  &handle_post_order_finished,
                                  po);
  return po;
}


/**
 * Cancel a POST /proposal request.  This function cannot be used
 * on a request handle if a response is already served for it.
 *
 * @param po the proposal operation request handle
 */
void
TALER_MERCHANT_orders_post_cancel (
  struct TALER_MERCHANT_PostOrdersOperation *po)
{
  if (NULL != po->job)
  {
    GNUNET_CURL_job_cancel (po->job);
    po->job = NULL;
  }
  GNUNET_free (po->url);
  TALER_curl_easy_post_finished (&po->post_ctx);
  GNUNET_free (po);
}


/* end of merchant_api_post_orders.c */